The goal of any medical dressing is to promote the natural healing and/or regeneration processes by providing the tissues with the optimal conditions for the healing phenomenon.
The dressings may be divided into two general groups:                (a) open dressings, where a rather free exchange of matter (e.g. gases, fluids, germs) may take place between the wound and the external environment; and        (b) occlusive dressing, where an impermeable barrier separates the wound and its immediate environment from the external environment and the atmosphere.        
Basically, the occlusive dressings are made of impermeable films and the peripheries of their undersurface are coated with a thin layer of pressure sensitive, biocompatible adhesive. The dressings may contain various medicines in a form of thick gels, ointments or granules or even the film itself may be impregnated or medicated with the desired medicine. The open dressings are mostly made of porous or fibrous materials such as knotted fiber, gauze or non-woven cottons, wool or other natural or synthetic substances. Their contact with the wound surface may produce favorable healing conditions depending on the dressing nature and the exchange equilibrium with the external environment.
Obviously the occlusive dressings offer a better opportunity to control the wounds immediate environment, and to protect it from harmful external factors. The drawbacks of these dressings are their cost and complexity of application.
PCT Application No. WO 85/01439 discloses a protective waterproof covering for an animal body. The covering is a thin, flexible, lightweight waterproof material such as polyethylene and is shaped to conform to that part of the body to be covered. The covering has means for attachment to the body. The coverings may be attached using pressure sensitive adhesive applied about the edge region of the covering or by using elasticized bands.
EP-A 0 117 714 A2 discloses a device for protecting a wound comprising a pad of skin-protective and skin-curative adhesive material to which is secured a foldable sheet of liquid-impermeable material of larger area than the pad, marginal areas of said sheet being provided with a sealing means, and said sheet being located and dimensioned so that said sheet when folded over on itself is sealed in liquid-tight fashion around its edges to define a compartment.
PCT Application No. WO 96/15745 discloses a wound treatment device for attachment to a patient's skin surface which comprises a wound attachment portion lying in contact with a patient's skin surface, a wound treatment portion defining a wound treatment area on the patient's skin surface and a transition portion for coupling the attachment portion to the wound treatment portion which includes a membrane connected to the attachment portion proximate to the patient's skin surface and connected to a standoff included in the wound treatment portion.
DE-A-1963375 discloses a touch-free protection system for sensitive skin areas, characterized in that a distancing material comprising a gap or gaps is applied by using its self-adhesive property between a cover and a skin region.
PCT Application No. WO 85/01439 discloses a protective waterproof covering for an animal body. The covering is a thin, flexible, lightweight waterproof material such as polyethylene and is shaped to conform to that part of the body to be covered. The covering has means for attachment to the body. The coverings may be attached using pressure sensitive adhesive applied about the edge region of the covering or by using elasticized bands.
EP-A 0 117 714 A2 discloses a device for protecting a wound comprising a pad of skin-protective and skin-curative adhesive material to which is secured a foldable sheet of liquid-impermeable material of larger area than the pad, marginal areas of said sheet being provided with a sealing means, and said sheet being located and dimensioned so that said sheet when folded over on itself is sealed in liquid-tight fashion around its edges to define a compartment.
PCT Application No. WO 96/15745 discloses a wound treatment device for attachment to a patient's skin surface which comprises a wound attachment portion lying in contact with a patient's skin surface, a wound treatment portion defining a wound treatment area on the patient's skin surface and a transition portion for coupling the attachment portion to the wound treatment portion which includes a membrane connected to the attachment portion proximate to the patient's skin surface and connected to a standoff included in the wound treatment portion.
DE-A-1963375 discloses a touch-free protection system for sensitive skin areas, characterized in that a distancing material comprising a gap or gaps is applied by using its self-adhesive property between a cover and a skin region.
Two inherent problems of the present occlusive dressings are:
(a) the difficulty in occluding efficiently the irregular body's topography especially where large areas are involved; and
(b) the limitation in changing the nature of the dressing's contents and the occluded wound's micro environment without disrupting or replacing the entire dressing.
This is the reason why the existing occlusive dressings are rather small and specific, and are designed to be used only in small and usually chronic wounds such as pressure sores, legs ulcers and stomal wounds. At present, in addition to the traditional cotton gauze dressings, there exists a plethora
of other kinds of dressings made of natural or synthetic materials each designed to provide a specific factor or component to the healing process. Even if we were to assume that each dressing's claims are truly fulfilled, the complex healing process and its ever-changing demands require a close monitoring and selection of a new appropriate dressing from the ever-growing dressing's armamentarium to satisfy the new demands.
It is a purpose of this invention to overcome the drawbacks of existing occlusive dressing systems.
In particular, it is a purpose of this invention to provide an occlusive dressing system which can conform to and occlude any area of the body of a patient regardless of his size, shape, location or skin irregularities.
It is another purpose of this invention to provide such a system which may contain any medicament, other desired substances or a specific physical environment in the form of solids, gels, ointments, liquids, gases or electrical and magnetic fields.
It is a further purpose of the invention to provide such a system the contents of which may be changed as desired and thus increase, decrease, change or replace, without disrupting or changing the dressing itself.
It is a still further purpose of this invention to provide such a system which permits the physical features of the dressing to be designed to promote specific biological activities in the occluded micro-environment of the affected area.
It is a still further purpose of the invention to provide such a system which permits to control and modify the environment occluded and contained by the dressing without its disruption.
Other purposes and advantages of the invention will appear as the description proceeds.